chore: scaffold CMake build system

Add the CMake build for the Swift + C++ macOS port, mirroring the
refix layout: deps/ modules (Platform, Flags, Sanitizers, FindUnity),
per-module static libraries (usb, auth, mt76, gip, hid, api), a Swift
app entry point with a pure C bridge header, and a Unity test suite
behind BUILD_TESTING.

Swift requires the Ninja or Xcode generator; a guard in
CMakeLists.txt rejects anything else.

Co-Authored-By: qwen (qwen/qwen3.8-27b@q2_k_xl): scaffolded CMake build + tests

tests/CMakeLists.txt

@@ -0,0 +1,26 @@
+set(TEST_TARGETS "")
+
+add_executable(test_version test_version.cpp)
+target_include_directories(test_version PRIVATE "${CMAKE_SOURCE_DIR}/include")
+target_link_libraries(test_version PRIVATE xone_api Unity::Unity)
+target_compile_features(test_version PRIVATE cxx_std_23)
+target_compile_definitions(test_version PRIVATE XONE_VERSION="${PROJECT_VERSION}")
+add_test(NAME test_version COMMAND test_version)
+list(APPEND TEST_TARGETS test_version)
+
+add_executable(test_types test_types.cpp)
+target_include_directories(test_types PRIVATE "${CMAKE_SOURCE_DIR}/include")
+target_link_libraries(test_types PRIVATE Unity::Unity)
+target_compile_features(test_types PRIVATE cxx_std_23)
+add_test(NAME test_types COMMAND test_types)
+list(APPEND TEST_TARGETS test_types)
+
+add_custom_target(check
+    COMMAND ${CMAKE_CTEST_COMMAND}
+            --test-dir "${CMAKE_BINARY_DIR}"
+            --output-on-failure
+            --progress
+    WORKING_DIRECTORY "${CMAKE_BINARY_DIR}"
+    USES_TERMINAL
+    DEPENDS ${TEST_TARGETS}
+)

tests/test_types.cpp

@@ -0,0 +1,46 @@
+#include "unity.h"
+
+#include "common/types.hpp"
+
+void setUp() {}
+void tearDown() {}
+
+void test_store_le16_little_endian(void)
+{
+    std::uint8_t buf[2];
+    xone::store_le16(buf, 0x1234);
+    TEST_ASSERT_EQUAL_UINT8(0x34, buf[0]);
+    TEST_ASSERT_EQUAL_UINT8(0x12, buf[1]);
+}
+
+void test_load_le16_roundtrip(void)
+{
+    std::uint8_t buf[2] = { 0xCD, 0xAB };
+    TEST_ASSERT_EQUAL_UINT16(0xABCD, xone::load_le16(buf));
+}
+
+void test_store_le32_little_endian(void)
+{
+    std::uint8_t buf[4];
+    xone::store_le32(buf, 0xDEADBEEF);
+    TEST_ASSERT_EQUAL_UINT8(0xEF, buf[0]);
+    TEST_ASSERT_EQUAL_UINT8(0xBE, buf[1]);
+    TEST_ASSERT_EQUAL_UINT8(0xAD, buf[2]);
+    TEST_ASSERT_EQUAL_UINT8(0xDE, buf[3]);
+}
+
+void test_load_le32_roundtrip(void)
+{
+    std::uint8_t buf[4] = { 0x01, 0x02, 0x03, 0x04 };
+    TEST_ASSERT_EQUAL_UINT32(0x04030201, xone::load_le32(buf));
+}
+
+int main(void)
+{
+    UNITY_BEGIN();
+    RUN_TEST(test_store_le16_little_endian);
+    RUN_TEST(test_load_le16_roundtrip);
+    RUN_TEST(test_store_le32_little_endian);
+    RUN_TEST(test_load_le32_roundtrip);
+    return UNITY_END();
+}

tests/test_version.cpp

@@ -0,0 +1,22 @@
+#include "unity.h"
+
+#include "app/xone_api.h"
+
+#ifndef XONE_VERSION
+#define XONE_VERSION "0.1.0"
+#endif
+
+void setUp() {}
+void tearDown() {}
+
+void test_version_matches_project(void)
+{
+    TEST_ASSERT_EQUAL_STRING(XONE_VERSION, xone_version());
+}
+
+int main(void)
+{
+    UNITY_BEGIN();
+    RUN_TEST(test_version_matches_project);
+    return UNITY_END();
+}